Steel is a critical material for many aspects of modern life. Transport systems, communications, civil infrastructure, and industrial engineering could not survive without it, yet the steel industry is reported to be responsible for 5 – 7 % of anthropogenic CO2 emissions making it a major contributor to climate change. Efficient utilization of the carbon rich by‐products of steel production in order to avoid CO2 emissions is vital. Traditionally by‐product gases have been used as fuel‐gas for heating applications or for power generation. Alternative chemical applications are now being developed based upon utilization of the gases as raw materials for chemicals production.

A key element in converting steel mill gases to chemical feedstocks is a thorough removal of contaminants. This paper summarizes important aspects of designing and operating the gas treatment pilot plant at the Carbon2Chem technical center in Duisburg. Information is given on how synthesis gas for the production of methanol and ammonia is produced. The efficient purification and conditioning of the gases is demonstrated by way of example of ammonia synthesis. Measures for enhancing the flexibility of the pilot plant are explained and issues related to scale-up are discussed.